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纤维增强聚合物基复合材料(FRP)面临制造厚度为10mm以上的零件的技术挑战。这是因为零件体积与表面积比的增大以及纤维与树脂的较低的热导率,使得树脂固化过程中产生的大量的热量无法及时散去。随着零件的厚度增加,树脂温度会因为反应热的增加而超过其降解温度。因而,本文着眼于厚壁复合材料零件的高宽比效应对单组分树脂系统RTM6在制造商推荐的固化周期(MRCC)下的最大成型厚度及其固化模式的影响。RTM6是特别为航空业树脂传递塑模(RTM)工艺开发的树脂系统。首先通过差示扫描量热仪(DSC)和参数拟合确定RTM6的固化动力学参数,然后采用有限元法进行模拟分析零件最大成型厚度和固化前沿的扩展过程并与文献结果相比较。结果表明,高宽比对厚壁复合材料零件的最大成型厚度和固化前沿扩展模式均有显著影响。零件最大成型厚度与文献结果的吻合度误差范围为1～7%。相同零件厚度下,随着高宽比的增加,会产生胶凝顺序“由外至内”和“由内至外”两种截然相反的固化前沿扩展模式。通过用户自定义固化周期(UDCC),可以实现将固化前沿扩展模式“由外至内”优化为“由内至外”。综上所述,纤维增强厚壁复合材料零件设计制造过程中,零件的高宽比是一个必须考虑的重要因素。
Fiber Reinforced Polymer Matrix Composites (FRP) face the technical challenge of making parts with thicknesses above 10 mm. This is because the increase of the ratio of the volume of the part to the surface area and the low thermal conductivity of the fiber and the resin make it impossible for the large amount of heat generated during the curing of the resin to be dispersed in time. As the thickness of the part increases, the temperature of the resin will exceed its degradation temperature as the heat of reaction increases. Thus, this paper looks at the aspect ratio effect of thick-walled composite parts on the maximum molded thickness and curing mode of the one-component resin system RTM6 at the manufacturer’s recommended cure cycle (MRCC). RTM6 is a resin system developed specifically for the aerospace resin transfer molding (RTM) process. Firstly, the curing kinetics parameters of RTM6 were determined by differential scanning calorimetry (DSC) and parameter fitting. Then the finite element method was used to simulate and analyze the maximum thickness of the part and the expansion of the solidification front and compare with the literature results. The results show that the aspect ratio has a significant effect on the maximum thickness of the thick-walled composite parts and the curing frontal expansion mode. The maximum thickness of the part and the result of the literature agree with the error range of 1 ~ 7%. With the same thickness of the part, as the aspect ratio increases, there are two diametrically opposed solidification frontal extension modes of gelling order “outer-to-inner” and “inner-to-outer”. Through the user-defined curing cycle (UDCC), can be achieved by curing the frontal extension mode “from outside to inside ” to “from the inside to the outside ”. In summary, fiber-reinforced thick-walled composite parts design and manufacturing process, the aspect ratio of the parts is an important factor that must be considered.